1. Field of the Invention
The present invention generally relates to thermal silhouette targets and more specifically, to a multi-layer electrically heated thermal silhouette target for 25 meter zeroing of a weapon mounted Thermal Imaging Sensor.
2. Description of Prior Art
Thermal imaging Sensors (TIS) must be zeroed before being used on a weapon. The current method to zero a TIS utilizes a large heated E-Type silhouette target along with attaching a modified non-thermal 25 meter zeroing target. The target provides temperature difference by either having a hole cut into it (air temperature difference), or pasting a foil sticker (reflective temperature difference) on it. The heated E-Type silhouette must use a 110 VAC or a large 12/24 Vdc power source.
If a hole is used, the E-Type target will eventually heat up the paper and cause the hole to disappear a seen by the TIS because of an eventual lack of temperature difference. If the foil sticker is used, the precise angle the target presented to the soldier becomes critical, since if the target is not perfectly aligned, the soldier will not be able to spot the target.
While the prior art has reported using thermal silhouette targets none have established a basis for a specific technique and target that is dedicated to the task of resolving the particular problem at hand. What is needed in this instance is a self contained thermal silhouette target device and technique for 25 meter zeroing of a thermal imaging sensor that is substantially insensitive to angular adjustments to the target.
It is therefore one object of the invention to provide a thermal silhouette target device and technique that for 25 meter zeroing of a thermal imaging sensor is substantially insensitive to angular adjustments to the target.
There is disclosed a thermal silhouette target for viewing by a thermal imaging sensor (TIS). A high emissivity surface adjoins a conductive layer which when heated by a heating coil allows the high emissivity surface to be seen as a silhouette by a TIS. An insulative layer with the predetermined silhouette adjoins the heating coil and said conductive layer. A direct voltage source is removably coupled to lead wires of the heating coil. The TIS views the silhouette as substantially insensitive to angular adjustments of the thermal silhouette target to the TIS.
A thermal zeroing silhouette target device for zeroing a thermal imaging sensor (TIS) mounted on a weapon also utilizes the thermal silhouette target. A mask including a zeroing grid on its surface has centrally located thereon the thermal silhouette target with said lead wires protruding from the back surface of the mask. A pair of contacts on the mask allows for electrical connection to the direct voltage current source. The TIS views said silhouette as substantially insensitive to angular adjustments of said thermal silhouette target to the TIS so that after the mounted weapon is fired, groups of impact points can be measured regarding the zeroing grid.